Self-sealing tank connector

ABSTRACT

A fitting having a tapered threaded section, formed by flattopped threads gradually increasing in height, permits the fitting to be screwed into and permanently retained in an aperture in a wall of a semi-rigid tank. As the threaded section is screwed into the aperture the tank wall distorts increasingly and is then led into an annular relief section, following the threaded section, to captivate the fitting against axial movement. The connector also includes a resilient gasket lying in and encompassing the relief section on the outside of the tank. The gasket is held between, and is compressed by, the tank wall and a flange section of the fitting to provide a fluid-tight seal.

United States Patent Akers 51 Mar. 21, 1972 [54] SELF-SEALING TANKCONNECTOR 21 Appl. No.: 113,530

[52] US. Cl. ..285/158, 85/46, 285/200,

285/209, 285/220, 285/423 [51] Int. Cl. ..Fl613/04 [58] Field 01 Search..285/333,334, 340, 355,200,

Green....

FOREIGN PATENTS OR APPLICATIONS 106,651 5/1917 Great Britain ..285/209Primary ExaminerDave W. Arola Att0rr1ey-Donald W. Banner, William S.McCurry and John W. Butcher 5 7] ABSTRACT A fitting having a taperedthreaded section, formed by flattopped threads gradually increasing inheight, permits the fitting to be screwed into and permanently retainedin an aperture in a wall of a semi-rigid tank. As the threaded sectionis screwed into the aperture the tank wall distorts increasingly and isthen led into an annular relief section, following the threaded section,to captivate the fitting against axial move ment. The connector alsoincludes a resilient gasket lying in and encompassing the relief sectionon the outside of the tank. The gasket is held between, and iscompressed by, the tank wall and a flange section of the fitting toprovide a fluid-tight seal.

8 Claims, 5 Drawing Figures Patented March 21, 1912 v V 3,650,551

lnvenfor Edward G. Akers Attorney fiElLlF-SEAMNG TANK CONNECTUT:

BACKGROUND OF THE INVENTION This invention relates to a novel tankconnector to be secured in a hole of a semirigid tank accessible onlyfrom the outside. While the connector may be effectively closed andemployed merely as a plug for sealing the hole, it may be open from oneend to the other to serve as an adapter to facilitate a fluid couplingto and/or from the tank, and will be so described.

Connectors developed heretofore useful for mounting to semirigidfluid-storage tanks, including those tanks made of either metal orplastic, are of relatively expensive construction and time consuming toinstall. This is due in part to the inaccessibility of the interior ofsuch tanks, requiring that a connector be attached and locked to a tankfrom the outside. Prior connectors were consequently complex in natureand each included at least three separate, and independently movable,pieces or parts. Accordingly, there is presently a definite need for atank connector that not only is inexpensive to manufacture but may berapidly and easily installed. Both of these objectives have now been metby applicant's unique connector. Its cost is substantially less than anyprevious connector designed to serve the same purpose, and yet it may bequickly and simply affixed to a tank.

It is, therefore, an object of the invention to provide a new, improvedand economical selfsealing connector for mounting to a semirigid tank.

Another object is to provide a low cost tank connector that may also bequickly and simply installed.

It is a further object of the invention to provide a unique tankconnector which, once affixed to an aperture of a tank, cannot beremoved but may be rotated to any desired orienta tion.

SUMMARY OF THE INVENTIDIJ The self-sealing tank connector of theinvention may be permanently and nonremovably secured in an aperture ina wall of a semirigid tank which is accessible only from the outside.The connector comprises a fitting which is turn includes (a) a taperedthreaded section to be screwed into the aperture and having at least twoflat-topped starting threads gradually increasing from a minimum to amaximum height from the leading to the trailing end of the threadedsection, the maximum transverse dimensions at the leading and trailingends being respectively less than and greater than the diameter of theaperture, (b) a flange section to be located external to the tank andhaving a maximum dimension substantially greater than the diameter ofthe aperture, and (c) an annular groove relief section between thethreaded and flange sections and having a root diameter less than themaximum transverse dimension of the threaded section at its trailingend. The connector also comprises a resilient gasket lying in andsurround ing the relief section and to be positioned external to thetank. As the tapered threaded section is screwed into the aperture, thetank wall is initially deformed or distorted by the flattopped threadsand is then led or directed into the relief section to captivate theconnector against removal even if the fitting is subsequently rotated ineither direction. The gasket, held between the flange section and thewall, provides a iluidtight seal.

DESCRIPTION OF THE DRAWING The features of the invention which arebelieved to be novel are set forth with particularity in the appendedclaims. The invention, together with further objects and advantagesthereof, may best be understood, however, by reference to the followingdescription in conjunction with the accompanying draw ing, in theseveral figures of which like reference numerals identify like elements,and in which:

FIG. I is a perspective, exploded view ofa portion ofa fluid storagetank and of a self-sealing tank connector, constructed in accordancewith one embodiment of the invention, to be screwed into an aperture inthe illustrated tank;

H6. 2 is a side view of the connector as it appears after it is mountedto the tank;

FIG. 3 is a sectional view taken along section line 3-3 in MG. 2;

FIG. 4 is a sectional view taken along section line 4-4 in FIG. 2; and,

FIG. 5 is a sectional view of only one element (the fitting) of theconnector and is taken along section line 5-5 in FIG. 3.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENT The disclosed tank connector(generally indicated by the reference numeral 10) may be attached to anyfluid storage tank whose walls are semirigid or deformable. Hence, tank12 may be constructed of any suitable material, such as metal orplastic, so long as its walls are susceptible to being distorted. Tank112 may also be used to store any desired fluid. As one very specificexample, the tank may be made of polyethylene plastic and may beemployed as a water tank for mobile homes and house trailers.

Connector 10 comprises only two separate elements or piecesa fitting I4and a resilient gasket 16. This is in sharp contrast to all priorconnectors for tanks. Fitting 14 is divided into and includes fourdifferent sections each of which serves a different purpose. In briefthe fitting has, between its two ends and in the order named, a taperedthreaded section 18, an annular groove relief section 21, a flangesection 24, and a nozzle section 26. Fitting M may be constructed of anysuitable material, such as metal or plastic, and may be formed in anyappropriate manner, for example by molding when plastic is used or bydie casting when metal is employed.

Considering now the construction of fitting 14 in more detail, twocharacteristics of the threaded section combine to provide the taperedconfiguration. Initially, the root diameter gradually increases from aminimum to a maximum dimension from the leading to the trailing end ofthe threaded section, namely from the left end to the right. end ofsection 18 as viewed in FIG. 2. In addition, and of greater importance,there are two flat-topped or squarecut starting threads 18a, 18b each ofwhich gradually increases from a minimum height (zero in the disclosedembodiment) to a maximum height from the leading to the trailing end ofthreaded section 18. In the illustrated case, the threads are of theacme type although any flat-topped thread will suffice; for example thebuttress type thread can be used. Flat-topped threads are necessary toavoid cutting or grinding material from the peripheral edge of aperture12a; this is important for reasons to be understood.

Since each of threads 18a, 18b starts out with zero height, threadedsection 18 presents a circular cross section at its leading end, as isbest seen in FIG. 3. The diameter of that cross section (dimension d, inFIG. 3) is therefore the maximum transverse dimension at the leading endand this is less than the diameter of aperture ll2a in tank 12. Thesmall end of tapered threaded section 18 may thus easily be insertedinto aperture 12a as the first step in mounting the connector to thetank. The maximum transverse dimension at the trailing end, indicated bythe dimension d in FIG. 3, in made greater than the diameter of hole12a. However, threaded section 18 may still be screwed into the aperturewithout cutting material from the edge of aperture l2a. After thethreaded section is inserted into aperture 12a and then rotatedclockwise, the flattopped threads deform the tank wall surrounding theaperture thereby permitting the threaded section to advance into theaperture. This operation may most easily be done by cocking or cantingfitting 14 so that the tank wall follows the root diameter. In this way,the wall is distorted by only one of the threads at a time. Of course,the polygonal shape (six sided in the illustrated embodiment) of flangesection 24 allows the use of a wrench for rotating the fitting tosimplify further the process of screwing the fitting into the tank wall.

The increasing thread height and root diameter combine to causeincreasing distortion of the tank wall as the trailing end approachesand reaches the aperture. Continued clockwise rotation thereafter leadsthe tank wall into relief section 21,

the root diameter of which is less than the dimension d and in theillustrated case is equal to the root diameter of the threaded sectionat its trailing end and this is preferably equal to the diameter ofaperture 12a. Hence, when the tank wall enters the relief section itwill return or spring back to its original or normal shape. By requiringsubstantial deformation of the tank wall before it can enter the reliefsection, captivation of the fitting against axial movement toward thetank exterior is achieved since any subsequent rotation in eitherdirection will be totally ineffective. Once the fitting has been screwedinto aperture 12a, there is no way that it can be unscrewed and removed.Of course, since flange section 24 has a maximum dimension substantiallygreater than the diameter of the aperture, the fitting is locked againstaxial movement in the direction toward the interior of the tank.

It is to be appreciated that the locked retention of the connector isdirectly attributable to the use of flat-topped threads which will notgrind and remove material from the edge of aperture 121:, as would bethe case if standard threads were employed as in a sheet metal screw.With standard threads it would be possible to unscrew the threadedsection.

Resilient gasket 16 surrounds relief section 21 on the outside of thetank and is held between flange section 24 and the tank wall to providea fluidtight seal. Preferably, the gasket is given a normal thicknesswhich, when added to the wall thickness, totals to a dimension greaterthan the separation between the threaded and flange sections. In thisway, the gasket will be compressed to insure a fluidtight seal. Thisfeature is particularly advantageous to compensate for unequal wallthickness.

Threads 18:: and 18b are shaped at the trailing end of the threadedsection to maximize the land or contact areas which bear against theinternal surface of the tank. These land areas, best seen in FIG. 4, areparallel to the tank wall and extend over approximately 120 of the 360periphery of the aperture. This has been found to be quite adequate tomaintain the connector squarely mounted and to prevent it from cocking.It is to be particularly noted that such wide-angle support is obtainedby means of only two starting threads. Of course, additional startingthreads could be employed to increase further the extent of contactbetween the threads and the tank wall.

, Tapering of the root diameter from the leading to the trailing end ofthreaded section 18 has been done to insure asnug fit in the event thatthe aperture is not properly sized. Such root diameter tapering,however, is not necessary. All that is needed is to increase the threadheight in going from the leading to the trailing end.

Fitting 14 is bored or hollowed out to provide a conduit 28 extendingalong its axis to facilitate fluid flow to and/or from the tank. Nozzlesection 26 is barbed so that a hose type fluid line may be' attachedthereto to couple to conduit 28. If desired, the nozzle section may beelbow shaped and at any required angle for the particular installationfor which the connector is designed. Inasmuch as the mounted connectormay always be rotated, the elbow fitting can be oriented in anypreferred direction over 360.

Applicant has therefore provided a unique two-piece, fluidtight tankconnector that may be installed faster and more simply than any previousconnector. Moreover, and of substantial importance, the inventionrealizes manufacturing economies never even approached heretofore. Thecost of applicants connector is only a small fraction of the cost of anyprior connector capable of performing the same function.

While a particular embodiment of the invention has been shown anddescribed, modifications may be made, and it is intended in the appendedclaims to cover all such modifications as may fall within the truespirit and scope of the invention.

1 claim:

1. A self-sealing tank connector for permanent non-removable attachmentin an aperture in a wall of a semirigid tank accessible only from theoutside, comprising:

a fitting including a tapered threaded section to be screwed into theaperture and having at least two flat-topped starting threads beingflat-topped throughout their entire length and gradually increasing froma minimum to a maximum height from the beginning of the leading to theend of the trailing end of said threaded section, the maximum transversedimensions at the leading and trailing ends being respectively less thanand greater than the diameter of the aperture, a flange section attachedto said fitting to be located external to the tank and having a maximumtransverse dimension substantially greater than the diameter of theaperture, and an annular groove relief section between said threaded andflange sections and having a root diameter less than the maximumtransverse dimension of said threaded section at its trailing end;

and a resilient gasket lying in and surrounding said relief section andto be positioned external to the tank;

the tank wall, as said tapered threaded section is screwed into theaperture, initially being deformed by said flattopped threads and thenbeing led into said relief section to captivate said connector againstremoval even if said fitting is subsequently rotated in eitherdirection,

said gasket being held between said flange section and the wall andproviding a fluidtight seal.

2. A self-sealing tank connector according to claim 1 in which saidrelief section separates said threaded and flange sections apredetermined distance greater than the thickness of the wall, and inwhich said resilient gasket has a thickness greater than the differencebetween said predetermined distance and the wall thickness, said gasketbeing compressed by said flange section and the wall.

3. A self-sealing tank connector according to claim 1 in which each ofsaid threads has substantially zero height at the leading end of saidthreaded" section.

4. A self-sealing tank connector according to claim 1 in which each ofsaid threads is of the acme type.

5. A self-sealing tank connector according to claim 1 in which the rootdiameter of said threaded section also gradually increases from aminimum to a maximum dimension from the leading to the trailing end, themaximum root diameter equaling that of said relief section.

6. A self-sealing tank connector according to claim 1 in which theperiphery of said flange section is polygonally shaped to permit the useof a wrench for rotating said fitting to screw said threaded sectioninto the aperture.

7. A self-sealing tank connector according to claim 1 in which each ofsaid threads is shaped at the trailing end to provide a land area ofmaximum size and which is parallel to the wall, and in which said gasketintroduces a force to press the internal surface of the tank against andin contact with each land area. I

8. A self-sealing tank connector according to claim 1 in which saidfitting is bored to provide a conduit to facilitate fluid flow from thetank and through said fitting, and in which said fitting also includes anozzle section to which a fluid line may be attached in order to coupleto said conduit.

1. A self-sealing tank connector for permanent non-removable attachmentin an aperture in a wall of a semirigid tank accessible only from theoutside, comprising: a fitting including a tapered threaded section tobe screwed into the aperture and having at least two flat-toppedstarting threads being flat-topped throughout their entire length andgradually increasing from a minimum to a maximum height from thebeginning of the leading to the end of the trailing end of said threadedsection, the maximum transverse dimensions at the leading and trailingends being respectively less than and greater than the diameter of theaperture, a flange section attached to said fitting to be locatedexternal to the tank and having a maximum transverse dimensionsubstantially greater than the diameter of the aperture, and an annulargroove relief section between said threaded and flange sections andhaving a root diameter less than the maximum transverse dimension ofsaid threaded section at its trailing end; and a resilient gasket lyingin and surrounding said relief section and to be positioned external tothe tank; the tank wall, as said tapered threaded section is screwedinto the aperture, initially being deformed by said flat-topped threadsand then being led into said relief section to captivate said connectoragainst removal even if said fitting is subsequently rotated in eitherdirection, said gasket being held between said flange section and thewall and providing a fluidtight seal.
 2. A self-sealing tank connectoraccording to claim 1 in which said relief section separates saidthreaded and flange sections a predetermined distance greater than thethickness of the wall, and in which said resilient gasket has athickness greater than the difference between said predetermineddistance and the wall thickness, said gasket being compressed by saidflange section and the wall.
 3. A self-sealing tank connector accordingto claim 1 in which each of said threads has substantially zero heightat the leading end of said threaded section.
 4. A self-sealing tankconnector according to claim 1 in which each of said threads is of theacme type.
 5. A self-sealing tank connector according to claim 1 inwhich the root diameter of said threaded section also graduallyincreases from a minimum to a maximuM dimension from the leading to thetrailing end, the maximum root diameter equaling that of said reliefsection.
 6. A self-sealing tank connector according to claim 1 in whichthe periphery of said flange section is polygonally shaped to permit theuse of a wrench for rotating said fitting to screw said threaded sectioninto the aperture.
 7. A self-sealing tank connector according to claim 1in which each of said threads is shaped at the trailing end to provide aland area of maximum size and which is parallel to the wall, and inwhich said gasket introduces a force to press the internal surface ofthe tank against and in contact with each land area.
 8. A self-sealingtank connector according to claim 1 in which said fitting is bored toprovide a conduit to facilitate fluid flow from the tank and throughsaid fitting, and in which said fitting also includes a nozzle sectionto which a fluid line may be attached in order to couple to saidconduit.